Frederick Little (Hugh Laurie) and Eleanor Little (Geena Davis) go to an orphanage to adopt a little brother for their son George (Jonathan Lipnicki). His wishes are granted literally when the Littles adopt the cute young mouse Stuart (voiced by Michael J. Fox) and bring him home. To begin with, George is very disappointed that he does not have a little boy for a brother, but soon he gets close...

Frederick Little (Hugh Laurie) and Eleanor Little (Geena Davis) go to an orphanage to adopt a little brother for their son George (Jonathan Lipnicki). His wishes are granted literally when the Littles adopt the cute young mouse Stuart (voiced by Michael J. Fox) and bring him home. To begin with, George is very disappointed that he does not have a little boy for a brother, but soon he gets close to Stuart. But will Snowbell, their cat, accept Stuart for her master?